1. Field of the Invention
The present invention relates in general to movable robots, and more particularly to a movable robot in which sensitivities of infrared-ray receivers for sensing obstacles can be controlled.
2. Description of the Prior Art
Generally, movable robots are disposed in homes and other places requiring the premises to be guarded. Such a movable robot moves in a predetermined zone under a command of tile user to keep watch for intruders. Upon appearance of an intruder during movement, the movable robot senses a thermal infrared-ray of a natural frequency reflected off the intruder and gives an alarm.
In addition to a thermal infrared-ray sensor for sensing the reflected thermal infrared-ray from the intruder, the movable robot comprises a plurality of ultrasonic wave sensors for sensing obstacles on a path along which the movable robot moves, thereby allowing the movable robot to avoid the obstacles during movement.
However, the above-mentioned conventional movable robot has a disadvantage in that it frequently collides with the obstacles in its path, such as fixtures, installations, etc. while moving in its predetermined zone to keep watch for intruders, since it fails to accurately sense the obstacles in the path of movement. Namely, the ultrasonic wave sensors in the conventional movable robot cannot accurately sense the obstacles on the moving path because they have large reflection errors. For this reason, for example, a flower vase may be broken in a collision with the movable robot. Also, when the movable robot collides with an object requiring attention, a safety accident may occur. This results in increased economic loss and added danger in work operations.